Current interrupter for electric cigar lighter

ABSTRACT

The current interrupter according to this invention has for its object to prevent overheating of electric cigar lighters. Said interrupter includes a tube which is made of thermoplastic resin of low inflammability. Within said tube, the terminal of the cigar lighter and an auxiliary terminal are placed coaxially and in contact with each other by means of a spring. When the cigar lighter has reached above the predetermined temperature, said thermoplastic tube softens and deforms axially by the action of the spring whereby as the contact between said terminals breaks, the current supply to the cigar lighter will be suspended at once.

Inaba Aug. 13, 1974 CURRENT INTERRUPTER FOR ELECTRIC CIGAR LIGHTER [75] Inventor: Shigeru Inaba, Kanagawa, Japan [73] Assignee: Niles Parts Co., Ltd., Tokyo, Japan [22] Filed: July 16, 1973 [2]] Appl. No.: 379,734

[52] US. Cl 337/382, 219/264, 337/394 [51] Int. Cl. H01h 37/46 [58] Field of Search 219/262, 263, 264, 265,

[56] References Cited UNITED STATES PATENTS 1,100,383 6/1914 Lorimer 337/394 X 1,935,762 11/1933 Appelberg l 337/399 X 2,270,564 1/1942 Schroeder 219/263 2,704,318 3/1955 Jorgenscn et a1. 219/264 2,711,457 6/1955 Wise 337/394 2,799,748 7/1957 Stump 337/394 X 2,883,510 4/1959 Krautwurst et a1. 219/264 2,988,618 6/1961 Houser 337/137 3,423,714 1/1969 Adam 3,680,022 7/1972 Bright 337/394 X Primary E.\'aminer Volodymyr Y. Mayewsky Attorney, Agent, or Firm-Hauke, Gifford, Patalidis & Dumont 5 7 ABSTRACT The current interrupter according to this invention has for its object to prevent overheating of electric cigar lighters. Said interrupter includes a tube which is made of thermoplastic resin of low inflammability. Within said tube, the terminal of the cigar lighter and an auxiliary terminal are placed coaxially and in contact with each other by means of a spring. When the cigar lighter has reached above the predetermined temperature, said thermoplastic tube softens and deforms axially by the action of the spring whereby as the contact between said terminals breaks, the current supply to the cigar lighter will be suspended at once.

1 Claim, 4 Drawing Figures CURRENT INTERRUPTER FOR ELECTRIC CIGAR LIGHTER BACKGROUND OF THE INVENTION This invention relates to an over-temperature current interrupter for electric cigar lighters of the type having a manually removable igniting plug which has an igniting coil that is electrically heated in a socket and removable therefrom for use to ignite tobacco.

The igniting plug includes a unitary assembly having at one end a cup into which the igniting coil is fixed to be usable. The socket is provided with bimetallic fingers for grasping said cup when in use.

In this type of electric cigar lighters, it often occurs that due to defects the bimetallic fingers, they fail to release the plug after the igniting coil has reached a predetermined tobacco igniting temperature which causes overheating of the cigar lighter. Such overheating not only damages the cigar lighter but also produces a fire hazard.

SUMMARY OF THE INVENTION This invention has for its object the elimination of damage to cigar lighters from excessive heat and the prevention of fire by providing a safeguard against overheating of cigar lighters.

According to this invention, the terminal of the socket and an auxiliary terminal are encased within a tube which is made of thermoplastic resin of low inflammability. These two terminals are placed coaxially and in contact with each other by means of a spring so when the temperature of the cigar lighter rises abnormally high, the tube will soften and deform axially by the action of the spring whereby as the contact between the two terminals is broken, and the supply of electricity to the cigar lighter will be suspended at once.

BRIEF DESCRIPTION OF THE DRAWINGS This invention is illustrated in a preferred embodiment in the accompanying drawings, in which;

FIG. 1 shows an igniting plug and socket of an electric cigar lighter provided with the current interrupter according to this invention;

FIG. 2 shows the current interrupter with partially sectional view;

FIG. 3 shows a partial sectional view of the current interrupter with power cord and electrical insulating boot attached shortly after overheating of the cigar lighter has begun; and

FIG. 4 shows the current interrupter in FIG. 3 at a point later in time when electrical power has been removed from the cigar lighter through the action of the current interrupter.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, the electric cigar lighter includes a removable igniting plug and a socket 12 which is provided with bimetallic fingers (not shown) which, in a manner well known in the art, conduct electricity to the plug 10 when in engagement therewith to heat the igniting coil 14 and release the plug 10 after the coil 14 has reached a predetermined tobacco igniting temperature. For a more detailed description of this type of electric cigar lighters, reference is had to US.

Pat. No. 3,088,015 granted Apr. 30, 1963 to J. H. Cone et al.

Due to defects of said bimetallic fingers, often they fail to release the plug even after the coil 14 has reached a predetermined tobacco igniting temperature whereby overheating of the cigar lighter results. Such overheating not only damages the cigar lighter but also produces a fire hazard.

This invention has for its object to prevent overheating by providing the cigar lighter with a heat sensitive device between the socket and a power source. Said device includes a tube 16 which is made of thermoplastic resin of low inflammability such as polyamide (66- nylon), methyl-styrol or the like. Said tube has a threaded aperture in which the threaded terminal 20 of the socket 12 is threaded so as to bring one end of said terminal into contact with the flat head 26 of a movable auxiliary terminal 24. A coil spring 22 is placed between said head 26 and an inwardly turned lip 28 of the tube l6 18 is a nut for facilitating the rotation of the tube 16 during the threading operation and is formed along a portion of the tube.

When the cigar lighter begins to overheat, the thermoplastic tube 16 softens and deforms as it is driven away from the threaded terminal 20 on the socket 12 by the action of the spring 22. As the tube 16 softens, it droops downwardly by the weight of the movable auxiliary terminal 24, the spring 22, electrical power conductors 30, and an electrical insulating boot 32. The deformation of the thermoplastic tube 16 continues until, as is shown in FIG. 4, the tube 16 falls away from threaded terminal 20, permanently breaking the electrical connection between terminals 20 and 24. Removal of current from the cigar lighter prevents damage to the lighter from excessive overheating and eliminates the hazard of fire.

Having thus described the invention, what is claimed as new is:

1. An over-temperature current interrupter for use in combination with electric cigar lighters of the type wherein a manually removable igniting plug having an igniting coil is inserted into a socket for heating by electric current which is supplied to the igniting coil through a first electrical terminal at the rear of the socket, wherein the improvement comprises:

a tube of thermoplastic resin of low inflammability which softens and deforms when a predetermined temperature is reached;

thread means attached to said tube for coaxially engaging said first terminal at the rear of said socket;

a second electrical terminal movably disposed within said tube; and spring means disposed within said tube for normally holding said first terminal and said second terminal in contact with each other and for urging separation of said tube from said socket; said tube having an inner lip portion and one end of said spring means engaging said inner lip portion, said spring means separating said tube and said socket upon said tube softening and deforming and thus separating said terminals upon deformation of said tube. 

1. An over-temperature current interrupter for use in combination with electric cigar lighters of the type wherein a manually removable igniting plug having an igniting coil is inserted into a socket for heating by electric current which is supplied to the igniting coil through a first electrical terminal at the rear of the socket, wherein the improvement comprises: a tube of thermoplastic resin of low inflammability which softens and deforms when a predetermined temperature is reached; thread means attached to said tube for coaxially engaging said first terminal at the rear of said socket; a second electrical terminal movably disposed within said tube; and spring means disposed within said tube for normally holding said first terminal and said second terminal in contact with each other and for urging separation of said tube from said socket; said tube having an inner lip portion and one end of said spring means engaging said inner lip portion, said spring means separating said tube and said socket upon said tube softening and deforming and thus separating said terminals upon deformation of said tube. 